RESUMEN
PURPOSE: To evaluate depth of focus (DOF) and visual acuities (VAs) by manifest refractive spherical equivalent (MRSE) and degree of preoperative corneal astigmatism with the IC-8® small aperture intraocular lens (SA IOL) (AptheraTM, Bausch & Lomb, Inc). SETTING: 21 investigational sites in the United States. DESIGN: Prospective, multi-center, open-label, parallel-group, non-randomized, examiner-masked, one-year clinical study. METHODS: Included patients had cataract and ≤1.5D preoperative corneal astigmatism. Patients received either the SA IOL in one eye targeted to -0.75D and a monofocal or monofocal toric IOL in the other targeted to plano (SA IOL Group) or bilateral monofocal/monofocal toric IOLs targeted to plano (Control Group). Monocular and binocular assessments included defocus curves and uncorrected VAs (distance, intermediate, and near) by postoperative MRSE; monocular VAs were assessed by degree of preoperative corneal astigmatism. RESULTS: The SA IOL Group (n=343) achieved 0.82D additional binocular DOF versus the Control Group (n=110), and SA IOL eyes achieved 0.91D additional monocular DOF over fellow eyes. Across all MRSEs, the SA IOL Group achieved monocular uncorrected VAs of 20/40 or better and binocular uncorrected VAs of 20/32 or better across all distances. Additionally, SA IOL eyes with higher (1.0-1.5D) versus lower (<1.0D) preoperative corneal astigmatism achieved equivalent monocular uncorrected VAs. CONCLUSIONS: The SA IOL provides increased DOF versus monofocal/monofocal toric IOLs and consistent monocular and binocular vision across several postoperative MRSEs and up to 1.5D of preoperative corneal astigmatism, giving patients with cataract and mild astigmatism the potential for an extended range of vision and reliable visual outcomes.
RESUMEN
Correction of corneal astigmatism is a key element of cataract surgery, since post-surgical residual astigmatism can compromise the patient's uncorrected visual acuity. Toric intraocular lenses (IOLs) compensate for corneal astigmatism at the time of surgery, correcting ocular astigmatism. They are a predictable treatment. However, accurate measurement of corneal astigmatism is mandatory for choosing the correct toric IOL power and for planning optimal alignment. When calculating the power of toric IOLs, it is important to consider anterior and posterior corneal astigmatism, along with the surgically induced astigmatism. Accurate toric lens alignment along the calculated meridian is also crucial to achieve effective astigmatism correction. There are several techniques to guide IOL alignment, including the traditional manual marking technique and automated systems based on anatomic and topographic landmarks. The aim of this review is to provide an overview on astigmatism management with toric IOLs, including relevant patient selection criteria, corneal astigmatism measurement, toric IOL power calculation, toric IOL alignment, clinical outcomes and complications.
O tratamento do astigmatismo corneal é um fator importante na cirurgia de catarata, uma vez que o astigmatismo residual pode comprometer a acuidade visual não corrigida do paciente após a cirurgia. Lentes intraoculares (LIOs) tóricas compensam o astigmatismo corneal no momento da cirurgia, corrigindo o astigmatismo ocular. Ademais, constituem um tratamento previsível. Entretanto, é necessário obter uma medida precisa do astigmatismo corneal para selecionar o poder correto da LIO tórica e para planejar o melhor alinhamento da mesma. No cálculo do poder da LIO tórica, é importante considerar o astigmatismo das superfícies anterior e posterior da córnea, além do astigmatismo induzido na cirurgia. O alinhamento da lente tórica no meridiano planejado é essencial para se obter uma correção efetiva do astigmatismo. Há várias técnicas para guiar o alinhamento da LIO, incluindo a técnica de marcação manual tradicional e sistemas que se baseiam em pontos de referência anatômicos e topográficos. O objetivo desse artigo de revisão é discutir o uso de LIOs tóricas no tratamento de astigmatismo corneal, incluindo os critérios de seleção dos pacientes, a medida do astigmatismo corneal, o cálculo do poder da LIO tórica, o alinhamento da LIO tórica, os resultados clínicos e as complicações.